ARM: S3C24XX: change the ARCH_S3C2410 to ARCH_S3C24XX

This patch changes the ARCH name to "ARCH_S3C24XX" for Samsung
S3C2410, S3C2412, S3C2413, S3C2416, S3C2440, S3C2442, S3C2443,
and S3C2450 SoCs so that we can merge the mach-xxx directories
and plat-s3c24xx dir. to just one mach-s3c24xx for them.

I think this should be sent to upstream via samsung tree because
this touches many samsung stuff.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Ball <cjb@laptop.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
[for the gadget part:]
Acked-by: Felipe Balbi <balbi@ti.com>
[for the framebuffer (video) part:]
Acked-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
[For the watchdog-part:]
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Sangbeom Kim <sbkim73@samsung.com>
Cc: Liam Girdwood <lrg@ti.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>